1. Field of the Invention
This invention relates to a system for and a method of detecting the condition of combustion in an engine.
2. Description of the Prior Art
In spark ignition internal combustion engines, spark timing closely relates to engine power output. The timing at which the pressure in the engine combustion chamber peaks depends on the spark timing. It is known to adjust spark timing so that the timing at which the pressure in the engine combustion chamber peaks coincides with a preset engine crank angle, thereby achieving optimal engine power output performance.
The December 1976 issue of the Journal of Dynamic Systems, Measurement, and Control, pages 414-420, discloses such a spark timing control system.
SAE (Society of Automotive Engineers) document No. 790139 suggests a similar control system.
These spark timing control systems include device for detecting the timing at which the pressure in the engine combustion chamber reaches its maximal level.
When spark timing is excessively retarded or an excessively rich or lean air-fuel mixture is supplied to the engine, the peak or maximal pressures sometimes do not result from combustions.